Manufacturing method of semiconductor device and semiconductor device

ABSTRACT

A semiconductor device includes a die pad, which includes an upper surface and a lower surface, the upper surface forming a rectangular shape in plan view; a plurality of support pins that support the die pad; a plurality of inner leads arranged around the die pad; a plurality of outer leads connected to each of the inner leads; a semiconductor chip which includes a main surface and a back surface and in which a plurality of electrode pads is formed in the main surface; a plurality of wires which electrically couple the electrode pads of the semiconductor chip to the inner leads respectively; and a sealing body that seals the support pins, the inner leads, the semiconductor chip, and the wires. A first support pin of the plurality of support pins is integrally formed together with the die pad. The first support pin is terminated inside the sealing body.

The present application is a Continuation Application of U.S. patent application Ser. No. 13/968,289, filed on Aug. 15, 2013, which is based on Japanese Patent Application No. 2012-197142 filed on Sep. 7, 2012, the entire contents of which are hereby incorporated by reference.

CROSS-REFERENCE TO RELATED APPLICATION

The disclosure of Japanese Patent Application No. 2012-197142 filed on Sep. 7, 2012 including the specification, drawings and abstract is incorporated herein by reference in its entirety.

BACKGROUND

The present invention relates to a semiconductor device and a manufacturing method of the semiconductor device, and relates to, for example, a semiconductor device including support pins that support a die pad and to an effective technique to be applied to assembling the semiconductor device.

For example, as a lead frame device, Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2002-505523 (Patent Document 1) discloses a structure including a lead frame manufactured from a first material, a lot of leads, and a die pad manufactured from a second material.

SUMMARY

In a semiconductor device (semiconductor package) including support pins (also referred to as “support leads”) that support a die pad (also referred to as an “island”) on which a semiconductor chip is mounted, the support pins are arranged at, for example, corner portions or on opposing sides of the die pad and appropriately support the die pad.

Also in a semiconductor device having a structure in which a plurality of die pads is arranged in a row in order to mount a plurality of semiconductor chips, each die pad can be supported by three support pins (supported by three points) by using leads connected to outer leads also as support pins of the die pads, and thus the reliability of die bonding, wire bonding and the like is ensured.

However, when trying to increase the number of pins without changing the size (appearance size) of the semiconductor device main body for functional enhancement of the semiconductor device, it is necessary to provide an independent lead for a signal by reducing the number of support pins that support the die pad, and thus the number of support pins decreases and the die pad is supported by two points.

As a result, the support state of the die pad becomes unstable. Therefore, if an external load is applied to the die pad in an assembling process of the semiconductor device, the die pad is deformed or vibrated in the vertical direction, and thus trouble may occur in the process or the semiconductor chips and wires are damaged.

That is, in a die bonding process and a wire bonding process, a bonding failure may occur because the die pad vertically moves (vibrates) and sufficient load is not applied to the die pad, or in a resin molding process, the die pad vertically moves (vibrates), and thus the semiconductor chip and wires are damaged, resulting in a failure of wire disconnection or the like.

Note that, in the lead frame device disclosed in Patent Document 1, binding bars (the support pins) are manufactured from the first material and the die pad is manufactured from the second material. Therefore, the lead frame device has a frame structure in which the support pins and the die pad are formed of different materials and thereafter the support pins and the die pad are coupled to each other.

In such a frame structure, a coupling portion to the support pins is required in the die pad, and thus the die pad has to be considerably larger than the chip size. That is, the die pad cannot be reduced to the size as small as the chip size, and thus it is not possible to employ the above frame structure, in which, in a small semiconductor device, the support pins and the die pad are formed as different parts and thereafter they are coupled to each other.

An object of an embodiment disclosed in the present application is to provide a technique capable of enhancing the reliability of a semiconductor device.

The other problems and the new feature will become clear from the description of the present specification and the accompanying drawings.

A manufacturing method of a semiconductor device according to an embodiment includes the steps of providing a lead frame including a plurality of die pads and plurality of support pins, mounting a semiconductor chip over the die pads, electrically coupling, through wires, electrode pads of the semiconductor chip to inner leads, and forming a sealing body that seals the support pins, the semiconductor chip, and the wires. Furthermore, in the manufacturing method of a semiconductor device, the support pins include a first support pin connected to an outer lead, a second support pin that is arranged between two of the inner leads and that is connected to a tie bar, and a third support pin connected to a side of the die pad different from sides to which the first support pin and the second support pin are connected. The first, the second, and the third support pins are integrally formed together with each of the die pads.

According to the embodiment described above, it is possible to enhance the reliability of the semiconductor device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing an example of a structure of a semiconductor device of an embodiment as seen through a sealing body;

FIG. 2 is a cross-sectional view showing an example of a structure taken along A-A line in FIG. 1;

FIG. 3 is a cross-sectional view showing an example of a structure taken along B-B line in FIG. 1;

FIG. 4 is a flowchart showing an example of an assembling procedure of the semiconductor device shown in FIG. 1;

FIG. 5 is a process flow diagram showing an example of the partial assembling procedure shown in FIG. 4;

FIG. 6 is a process flow diagram showing an example of the partial assembling procedure shown in FIG. 4;

FIG. 7 is a process flow diagram showing an example of the partial assembling procedure shown in FIG. 4;

FIG. 8 is an enlarged partial plan view showing an example of a structure of a lead frame used in the assembling of the semiconductor device shown in FIG. 1;

FIG. 9 is a partial plan view showing stability of a die pad of the lead frame shown in FIG. 8;

FIG. 10 is an enlarged partial plan view showing an example of a separation method of second support pins in a package separation process in the assembling of the semiconductor device shown in FIG. 1;

FIG. 11 is a partial plan view showing a first modification of the separation method of the second support pins (before injecting a resin) in the assembling of the semiconductor device shown in FIG. 1;

FIG. 12 is an enlarged partial plan view showing a structure of a D portion in FIG. 11;

FIG. 13 is a partial plan view showing the first modification of the separation method of the second support pins (after injecting a resin) in the assembling of the semiconductor device shown in FIG. 1;

FIG. 14 is an enlarged partial plan view showing a structure of a G portion in FIG. 13;

FIG. 15 is an enlarged partial plan view showing a detailed structure of FIG. 14;

FIG. 16 is an enlarged partial plan view showing a structure of a lead frame of a second modification used in the assembling of the semiconductor device of the embodiment;

FIG. 17 is a partial plan view showing stability of die pads of the lead frame shown in FIG. 16;

FIG. 18 is an enlarged partial plan view showing a structure of a lead frame of a third modification used in the assembling of the semiconductor device of the embodiment;

FIG. 19 is a partial plan view showing stability of die pads of the lead frame shown in FIG. 18;

FIG. 20 is an enlarged partial plan view showing a structure of a lead frame of a fourth modification used in the assembling of the semiconductor device of the embodiment;

FIG. 21 is a partial plan view showing stability of die pads of the lead frame shown in FIG. 20;

FIG. 22 is an enlarged partial plan view and partial cross-sectional views showing a structure of a lead frame of a fifth modification used in the assembling of the semiconductor device of the embodiment;

FIG. 23 is an enlarged partial plan view showing a structure of a lead frame of a sixth modification used in the assembling of the semiconductor device of the embodiment;

FIG. 24 is a cross-sectional view showing a structure taken along A-A line in FIG. 23; and

FIG. 25 is an enlarged partial plan view and partial cross-sectional views showing a structure of a lead frame of a seventh modification used in the assembling of the semiconductor device of the embodiment.

DETAILED DESCRIPTION

In the embodiment described below, the description of the same or a similar portion is not repeated unless particularly required.

Furthermore, the following embodiment will be explained, divided into plural sections or embodiments, if necessary for convenience. Except for the case where it shows clearly in particular, they are not mutually unrelated and one has relationships such as a modification, details, and supplementary explanation of some or entire of another.

In the following embodiment, when referring to the number of elements, etc. (including the number, a numeric value, an amount, a range, etc.), they may be not restricted to the specific number but may be greater or smaller than the specific number, except for the case where they are clearly specified in particular and where they are clearly restricted to a specific number theoretically.

Furthermore, in the following embodiment, it is needless to say that an element (including an element step etc.) is not necessarily indispensable, except for the case where it is clearly specified in particular and where it is considered to be clearly indispensable from a theoretical point of view, etc.

In the following embodiment, regarding an element etc., it is needless to say that “comprise A”, “consist of A”, “have A”, and “include A” do not exclude elements other than A, except for the case where it is clearly specified that the element is only A. Similarly, in the following embodiments, when shape, position relationship, etc. of an element etc. is referred to, what resembles or is similar to the shape substantially shall be included, except for the case where it is clearly specified in particular and where it is considered to be clearly not right from a theoretical point of view. This statement also applies to the numeric value and range described above.

Hereinafter, the embodiment will be explained on the basis of the drawings. In all the drawings for explaining embodiments, the same symbol is attached to the same member and the repeated explanation thereof is omitted. In order to make a drawing intelligible, hatching may be attached even if it is a plan view.

Embodiment

FIG. 1 is a plan view showing an example of a structure of a semiconductor device of the embodiment as seen through a sealing body. FIG. 2 is a cross-sectional view showing an example of a structure taken along A-A line in FIG. 1. FIG. 3 is a cross-sectional view showing an example of a structure taken along B-B line in FIG. 1.

The semiconductor device of the embodiment shown in FIGS. 1 to 3 is a frame-type semiconductor package assembled by using a dual island-type lead frame 3 shown in FIG. 8 described below. In the present embodiment, as an example of the above-mentioned semiconductor device, a resin sealing-type 8-pin SOP (Small Outline Package) 7 is taken up and a structure and a manufacturing method of the SOP 7 will be described. That is, the semiconductor device of the present embodiment includes a plurality of die pads (islands, tabs), and in the present embodiment, the SOP 7 including two die pads will be taken up and described.

First, a structure of the SOP 7 will be described with reference to FIGS. 1 to 3. The SOP 7 includes a semiconductor chip 1 in which a semiconductor element (semiconductor integrated circuit) 1 d is formed, a semiconductor chip 2 in which a semiconductor element 2 d is formed, a die pad 3 a on which a semiconductor chip 1 is mounted, and a die pad 3 h on which a semiconductor chip 2 is mounted.

That is, the die pad 3 a and the die pad 3 h, which are two chip mounting portions, are arranged side by side, and the semiconductor chip 1 is mounted on an upper surface 3 aa of the die pad 3 a via a die bonding paste 5 formed of a solder paste. In contrast, the semiconductor chip 2 is mounted on an upper surface aha of the die pad 3 h via the same die bonding paste 5 formed of a solder paste.

Furthermore, the SOP 7 includes a plurality of (six) inner leads 3 b arranged around the die pads 3 a and 3 h, a plurality of (eight) outer leads 3 c integrally formed together with the inner leads 3 b, and a plurality of wires 6 which electrically couple the semiconductor chips 1 and 2 to the inner leads 3 b.

That is, in the SOP 7 of the present embodiment, the leads electrically coupled to electrode pads 1 c and 2 c via the wires 6 are defined as the inner leads 3 b, and there are six inner leads 3 b coupled to the wires 6, and the six inner leads 3 b are connected to the outer leads 3 c.

In addition, first support pins 3 d and 3 i of three support pins that support the die pad 3 a or 3 h are coupled to the outer leads 3 c respectively. Therefore, there are a total of eight outer leads 3 c including six outer leads 3 c coupled to the inner leads 3 b and two outer leads 3 c coupled to the first support pins 3 d and 3 i.

Note that the outer lead 3 c is not connected to a second support pin 3 e, a third support pin 3 f, a second support pin 3 j, and a third support pin 3 k.

In addition, as shown in FIGS. 1 and 2, a plurality of electrode pads 1 c formed on a front surface (main surface) 1 a of the semiconductor chip 1 is electrically coupled to a plurality of inner leads 3 b corresponding to the electrode pads 1 c, respectively, through a plurality of wires 6. In contrast, a plurality of electrode pads 2 c formed on a front surface (main surface) 2 a of the semiconductor chip 2 are electrically coupled to a plurality of inner leads 3 b corresponding to the electrode pads 2 c, respectively, through a plurality of wires 6.

Note that, since the SOP 7 is a wire bonding type, the semiconductor chip 1 is face-up mounted over the upper surface 3 aa of the die pad 3 a with the main surface (front surface) 1 a facing up.

That is, the upper surface 3 aa of the die pad 3 a and a back surface 1 b of the semiconductor chip 1 arranged so as to face the upper surface 3 aa are coupled to each other via the die bonding paste 5.

In contrast, the semiconductor chip 2 is face-up mounted over the upper surface 3 ha of the die pad 3 h with the main surface (front surface) 2 a facing up. That is, the upper surface 3 ha of the die pad 3 h and a back surface 2 b of the semiconductor chip 2 arranged so as to face the upper surface 3 ha are coupled to each other via the die bonding paste 5.

Furthermore, the electrode pads 1 c formed on the front surface 1 a of the semiconductor chip 1 are electrically coupled to the inner leads 3 b, respectively, via the wires 6. Thereby, the semiconductor chip 1, the inner leads 3 b, and the outer leads 3 c functioning as external terminals are electrically coupled to each other.

That is, one end of each of the wires 6 is electrically coupled to the electrode pad 1 c of the semiconductor chip 1. In contrast, the other end of each of the wires 6 is electrically coupled to the inner lead 3 b corresponding to each wire 6. In the same manner, the electrode pads 2 c formed on the front surface 2 a of the semiconductor chip 2 are also electrically coupled to the inner leads 3 b, respectively, via the wires 6. Thereby, the semiconductor chip 2, the inner leads 3 b, and the outer leads 3 c functioning as external terminals are electrically coupled to each other.

In addition, one end of each of the wires 6 is electrically coupled to the electrode pad 2 c of the semiconductor chip 2. In contrast, the other end of each of the wires 6 is electrically coupled to the inner lead 3 b corresponding to each wire 6.

Furthermore, the die pads 3 a and 3 h have the upper surfaces 3 aa and 3 ha, respectively, whose plan view is substantially rectangular, and have lower surfaces 3 ab and 3 hb, respectively, opposite to the upper surfaces 3 aa and 3 ha, and each of the die pads 3 a and 3 h is supported by three support pins.

That is, the die pad 3 a is supported by the first support pin 3 d connected to the outer lead 3 c, the second support pin 3 e arranged between two inner leads 3 b adjacent to each other, and the other third support pin 3 f. In the same way, the die pad 3 h is also supported by the first support pin 3 i connected to the outer lead 3 c, the second support pin 3 j arranged between two inner leads 3 b adjacent to each other, and the other third support pin 3 k.

Note that the upper surface 3 aa of the die pad 3 a includes a first side 3 ac, a second side 3 ad, a third side Sae and a fourth side 3 af, and the first support pin 3 d is connected to the first side Sac and the second support pin 3 e is connected to the second side Sad opposite to the first side 3 ac. Furthermore, the third support pin 3 f is coupled to the third side 3 ae different from both the first side Sac to which the first support pin 3 d is connected and the second side Sad to which the second support pin 3 e is connected.

In contrast, in the same manner as in the die pad 3 a, the upper surface aha of the die pad 3 h includes a first side 3 hc, a second side 3 hd, a third side She and a fourth side 3 hf, and the first support pin 3 i is connected to the first side 3 hc and the second support pin 3 j is connected to the second side 3 hd opposite to the first side 3 hc. Furthermore, the third support pin 3 k is connected to the third side 3 he different from both the first side 3 hc to which the first support pin 3 i is connected and the second side 3 hd to which the second support pin 3 j is connected.

Moreover, the first support pin 3 d, the second support pin 3 e, and the third support pin 3 f are integrally formed together with the die pad 3 a. In contrast, the first support pin 3 i, the second support pin 3 j, and the third support pin 3 k are integrally formed together with the die pad 3 h.

Note that no support pin is connected to the fourth side 3 af of the die pad 3 a and the fourth side 3 hf of the die pad 3 h, and the die pad 3 a and the die pad 3 h are arranged so that the fourth side 3 af and the fourth side 3 hf face each other.

In addition, the SOP 7 of the present embodiment is formed of a sealing resin 8 shown in FIG. 6 described later and includes the semiconductor chips 1 and 2, the die pads 3 a and 3 h, the wires 6, the inner leads 3 b, and a sealing body 4 that seals each support pin (3 d, 3 e, 3 f, 3 i, 3 j, and 3 k).

Meanwhile, it is preferable that the second support pin 3 e that supports the die pad 3 a and the second support pin 3 j that supports the die pad 3 h are terminated inside the sealing body. This is because, in a process of separating, from the lead frame 3, the support pins in an assembling process of the semiconductor device described later, there is employed an assembling method in which the second support pins 3 e and 3 j are torn off by a resin injection pressure in a sealing process and thereafter the tips of the second support pins 3 e and 3 j are covered by a resin.

Therefore, in the SOP 7, the tips of the respective second support pins 3 e and 3 j are buried inside the sealing body 4. However, the third support pins 3 f and 3 k are slightly exposed to the outside of the sealing body 4 as shown in FIG. 3 since, in a process of separating, from the lead frame 3, the support pins in the assembling process, there is employed an assembling method in which the third support pins 3 f and 3 k are cut off after a resin sealing process.

Note that, as to a method of separating the second support pins 3 e and 3 j from the lead frame 3, a method may be employed in which the second support pins 3 e and 3 j are cut off after the resin sealing process in the same manner as the third support pins 3 f and 3 k, and in this case, the second support pins 3 e and 3 j are slightly exposed to the outside of the sealing body 4 in the same manner as the third support pins 3 f and 3 k.

Here, the inner leads 3 b, the outer leads 3 c, the support pins, and the die pads 3 a and 3 h are formed of a thin plate member formed of, for example, a copper alloy, an iron-nickel alloy, or the like. In addition, the sealing body 4 includes, for example, a thermosetting epoxy resin and is formed in the resin sealing process.

The wires 6 are, for example, gold (Au) wires or copper (Cu) wires.

Furthermore, since the semiconductor device is the SOP 7, as shown in FIG. 2, the outer leads 3 c which are integrally formed together with the inner leads 3 b respectively, protrude outward from the side surfaces of the sealing body 4 in two directions opposite to each other, and each of the outer leads 3 c is bent and formed into a gull-wing shape.

Next, the assembling of the semiconductor device (SOP 7) of the present embodiment will be described with reference to a flowchart shown in FIG. 4. That is, in the present embodiment, as an example of the semiconductor device, an assembling of an 8-pin dual island-type SOP 7 will be described.

FIG. 4 is a flowchart showing an example of an assembling procedure of the semiconductor device shown in FIG. 1, FIG. 5 is a process flow diagram showing an example of the partial assembling procedure shown in FIG. 4, FIG. 6 is a process flow diagram showing an example of the partial assembling procedure shown in FIG. 4, and FIG. 7 is a process flow diagram showing an example of the partial assembling procedure shown in FIG. 4. In addition, FIG. 8 is an enlarged partial plan view showing an example of the structure of the lead frame used in the assembling of the semiconductor device shown in FIG. 1. FIG. 9 is a partial plan view showing stability of the die pad of the lead frame shown in FIG. 8. FIG. 10 is an enlarged partial plan view showing an example of a separation method of the second support pins in a package separation process in the assembling of the semiconductor device shown in FIG. 1.

First, the provision of the lead frame shown in step S1 in FIGS. 4 and 5 is performed. In the present embodiment, as shown in FIG. 8, there is provided the lead frame 3 in which two die pads (islands) 3 a and 3 h and two pairs of three support pins supporting the two die pads 3 a and 3 h, respectively, are provided. Furthermore, the lead frame 3 is provided with the inner leads 3 b arranged around the two die pads 3 a and 3 h, the outer leads 3 c connected to the inner leads 3 b respectively, and tie bars 3 g that couple the outer leads to each other.

Each outer lead 3 c arranged at an end portion of an outer lead array is connected to a frame portion 3 q through the tie bar 3 g.

Here, the die pad 3 a and the die pad 3 h are arranged side by side and have the upper surfaces 3 aa and 3 ha, respectively, whose planar view is substantially rectangular, and have the lower surfaces 3 ab and 3 hb, respectively, opposite to the upper surfaces 3 aa and 3 ha (see FIG. 3). Each of the die pads 3 a and 3 h is supported by three support pins. That is, each of the die pads 3 a and 3 h is supported at three points by the support pins.

Specifically, as shown in FIG. 8, the die pad 3 a is supported by the first support pin 3 d connected to the outer lead 3 c, the second support pin 3 e that is arranged between two inner leads 3 b adjacent to each other and that is connected to the tie bar 3 g, and the third support pin 3 f connected to the frame portion 3 q. In the same way, the die pad 3 h is also supported by the first support pin 3 i connected to the outer lead 3 c, the second support pin 3 j that is arranged between two inner leads 3 b adjacent to each other and that is connected to the tie bar 3 g, and the third support pin 3 k connected to the frame portion 3 q.

Note that the first support pin 3 d, the second support pin 3 e, and the third support pin 3 f are integrally formed together with the die pad 3 a. In contrast, the first support pin 3 i, the second support pin 3 j, and the third support pin 3 k are integrally formed together with the die pad 3 h.

In addition, the upper surface 3 aa of the die pad 3 a includes the first side 3 ac, the second side 3 ad, the third side Sae and the fourth side 3 af, and the first support pin 3 d is coupled to the first side 3 ac and the second support pin 3 e is coupled to the second side 3 ad connected to the first side 3 ac. Furthermore, the third support pin 3 f is connected to the third side 3 ae different from both the first side 3 ac to which the first support pin 3 d is connected and the second side 3 ad to which the second support pin 3 e is connected.

In contrast, in the same manner as in the die pad 3 a, the upper surface aha of the die pad 3 h includes a first side 3 hc, a second side 3 hd, a third side She and a fourth side 3 hf, and the first support pin 3 i is connected to the first side 3 hc and the second support pin 3 j is connected to the second side 3 hd opposite to the first side 3 hc. Moreover, the third support pin 3 k is connected to the third side 3 he different from both the first side 3 hc to which the first support pin 3 i is connected and the second side 3 hd to which the second support pin 3 j is connected.

Note that no support pin is connected to the fourth side 3 af of the die pad 3 a and the fourth side 3 hf of the die pad 3 h, and the die pad 3 a and the die pad 3 h are arranged so that the fourth side 3 af and the fourth side 3 hf face each other.

Here, the lead frame 3 including the inner leads 3 b, the outer leads 3 c, the support pins, the die pads 3 a and 3 h, the tie bars 3 g, the frame portion 3 q, and the like is formed by a thin plate member formed of, for example, a copper alloy, an iron-nickel alloy, or the like.

As described above, in the lead frame 3 of the present embodiment, each of the two die pads 3 a and 3 h has a three-point support configuration by the three support pins, and as shown in an A portion in FIG. 8, each of the second support pins 3 e and 3 j included in the two pairs of the three support pins is arranged between two inner leads 3 b adjacent to each other and coupled to the tie bar 3 g. Furthermore, the two pairs of three support pins are integrally formed together with the die pads 3 a and 3 h respectively.

Here, a balance (degree of stability) of a support form of the two die pads 3 a and 3 h in the lead frame 3 of the present embodiment will be described with reference to FIG. 9. FIG. 9 shows balances between support positions of the die pads 3 a and 3 h, each of which is supported by three points, in the lead frame 3 of the present embodiment. In each of the die pads 3 a and 3 h, a triangle is formed by using the support positions as points, and whether or not the shape of the triangle is well-balanced (whether or not the shape of the triangle has an extremely sharp angle) is evaluated.

As shown in FIG. 9, the shape of the triangle of both the triangle A of the die pad 3 a and the triangle B of the die pad 3 h is well-balanced, and thus it can be found that the die pads 3 a and 3 h are in a support state of a high degree of stability.

After the provision of the lead frame, the die bonding shown in step S2 in FIGS. 4 and 5 is performed. In the die bonding process, first, the die bonding paste coating shown in S2-1 in FIG. 5 is performed. That is, the die pads 3 a and 3 h of the lead frame 3 are coated with a solder paste that is the die bonding paste 5. Furthermore, the chip mounting shown in S2-2 in FIG. 5 is performed.

Here, as shown in FIG. 3, the semiconductor chip 1 is mounted, via the die bonding paste 5, over the upper surface 3 aa of the die pad 3 a and the semiconductor chip 2 is mounted, via the die bonding paste 5, over an upper surface aha of the die pad 3 h. Note that, as shown in FIG. 1, the electrode pads 1 c are formed on the front surface 1 a of the semiconductor chip 1 and the electrode pads 2 c are formed on the front surface 2 a of the semiconductor chip 2.

When the chips are mounted, a predetermined load is applied to the semiconductor chips 1 and 2. However, since each of the die pads 3 a and 3 h of the lead frame 3 of the present embodiment is supported with high stability at three points by the three support pins, it is possible to reduce the vertical movement (vibration) of the die pads 3 a and 3 h.

After the completion of the die bonding, the wire bonding shown in step S3 in FIGS. 4 and 6 is performed. In the wire bonding process, as shown in FIG. 1, the electrode pads 1 c of the semiconductor chip 1 and the electrode pads 2 c of the semiconductor chip 2 are electrically coupled, via the wires 6, to the inner leads 3 b corresponding to each electrode pad.

Even at the time of the wire bonding, a predetermined load or an ultrasonic wave is applied to the semiconductor chips 1 and 2. However, since each of the die pads 3 a and 3 h of the lead frame 3 of the present embodiment is supported with high stability at three points by the three support pins, it is possible to reduce the vertical movement (vibration) of the die pads 3 a and 3 h at the time of the wire bonding.

After the completion of the wire bonding, the resin sealing (resin molding) shown in step S4 in FIGS. 4 and 6 is performed. That is, the support pins, the semiconductor chips 1 and 2, the die pads 3 a and 3 h, the inner leads 3 b, and wires 6 are sealed by the sealing resin 8 shown in FIG. 6 and a sealing body 4 is formed.

At this time, the lead frame 3 to which the wires are bonded is arranged over a lower molding die 9 a of a resin molding die 9 as a work piece, then the lead frame 3 is clamped by the lower molding die 9 a and an upper molding die 9 b, and furthermore, a resin sealing is performed by injecting the sealing resin 8 into a cavity 9 c formed by the lower molding die 9 a and the upper molding die 9 b.

Even at the time of resin injection in the resin sealing process, a pressure due to the resin injection is applied to the semiconductor chips 1 and 2 and the die pads 3 a and 3 h. However, since each of the die pads 3 a and 3 h of the lead frame 3 of the present embodiment is supported with high stability at three points by the three support pins, it is possible to reduce the vertical movement (vibration) of the die pads 3 a and 3 h at the time of the resin injection.

After completion of the resin sealing, the post cure shown instep S5 in FIGS. 4 and 7 is performed. That is, the sealing body 4 formed in the resin sealing process and the like is heat-treated and cured.

After completion of the post cure, the deburring/external plating shown in step S6 in FIG. 4 is performed. That is, resin burrs and the like formed in the resin sealing process and the like are removed and external plating is applied to the outer leads 3 c and the like.

After completion of the deburring/external plating, the package separation/lead trim and form shown in step S7 in FIGS. 4 and 7 is performed. That is, as shown in FIG. 7, each of the outer leads 3 c is cut off and separated from the lead frame 3 and each outer lead 3 c is bent and formed. In the present embodiment, each outer lead 3 c is bent and formed into a gull-wing shape.

In the package separation process, as shown in FIG. 10, first, the tie bars 3 g between the outer leads 3 c adjacent to each other are cut off by a tie bar cut punch 10 (A portion), and at the same time, the second support pins 3 e and 3 j are cut off by the tie bar cut punch 10 (B portion and C portion).

Namely, since both the second support pins 3 e and 3 j are connected to the tie bars 3 g, both the second support pins 3 e and 3 j can be cut off by the tie bar cut punch 10 together with the tie bars 3 g. That is, both the second support pins 3 e and 3 j can be easily cut off without being left in the tie bar cut process.

After the package separation/lead trim and form, the characteristic screening shown in step S8 in FIG. 4 is performed. That is, an electrical characteristic test is performed on the assembled SOP 7 and defective or non-defective product is determined.

After the characteristic screening, the marking shown in step S9 is performed on the SOP 7 which is determined to be a non-defective product. Here, for example, information such as a model number or the like of the product is marked on the front surface of the sealing body 4.

After the marking, the taping shown in step S10 in FIG. 4 is performed and further the packing/shipping shown in step S11 is performed.

According to the manufacturing method of a semiconductor device and the semiconductor device of the present embodiment, two pairs of the three support pins supporting the die pads 3 a and 3 h include the first support pins 3 d and 3 i, the second support pins 3 e and 3 j, and the third support pins 3 f and 3 k, and furthermore each of the first support pins 3 d and 3 i, the second support pins 3 e and 3 j, and the third support pins 3 f and 3 k is integrally formed together with each of the two die pads 3 a and 3 h. Thereby, each of the die pads 3 a and 3 h is supported at three points, and thus it is possible to reduce the vertical movement (vibration) of each of the die pads 3 a and 3 h in the assembling process.

That is, each of the die pads 3 a and 3 h is supported in a balanced manner at three points, and thus it is possible to reduce the vertical movement (vibration) of each of the die pads 3 a and 3 h in the die bonding process, the wire bonding process and the like. Thereby, a sufficient load for bonding can be applied, and thus it is possible to suppress the occurrence of a bonding failure.

Since the die pads are supported in a balanced manner at three points, it is possible to reduce the vertical movement (vibration) of the die pads at the time of the resin injection in the resin sealing process. As a result, at the time of the resin injection, it is possible to reduce damage done to the semiconductor chips and the wires, and thus it is possible to suppress the occurrence of a defect such as a broken wire.

As a result, it is possible to enhance the reliability of the semiconductor device.

By arrangement of each of the second support pins 3 e and 3 j between the inner leads, it is possible to increase the number of pins of the semiconductor device without changing the size (appearance size) of the semiconductor device main body, and thus functional enhancement of the semiconductor device can also be addressed. That is, by connecting, to the tie bar 3 g, each of the second support pins 3 e and 3 j arranged between the inner leads 3 b, it is possible to support the die pads 3 a and 3 h without using signal pins. Thereby, it is possible to increase the number of signal pins, and thus the function of the semiconductor device can be enhanced.

Furthermore, by arrangement of each of the second support pins 3 e and 3 j between the inner leads 3 b, it is possible to ensure a distance between the inner leads 3 b adjacent to each other, and thus it is possible to prevent migration generated between the inner leads 3 b.

Note that, when the semiconductor device is a small semiconductor device, an area for performing the wire bonding is required in a second bonding portion (stitch bonding portion) of the inner leads 3 b, and thus it is not possible to bring the outer peripheries of the die pads 3 a and 3 h close to the outer periphery of the sealing body 4. That is, it is not possible to form each of the die pads 3 a and 3 h to be much larger than the semiconductor chips 1 and 2. Therefore, in the case of a frame structure in which the support pins and the die pads are formed as different parts and thereafter they are coupled to each other, a coupling portion to the support pins is required to be provided in the die pads. However, it is not possible to form the die pads to be much larger than the semiconductor chips 1 and 2, and as a result, there is no space to provide the coupling portion in the die pads, thereby it being difficult to employ the above frame structure. However, in the semiconductor device of the present embodiment, two pairs of three support pins are integrally formed together with the die pads 3 a and 3 h respectively, and thus the coupling portion is not required to be provided. Therefore, the size of the die pads 3 a and 3 h can be as small as the chip size. As a result, it is possible to address the reduction of the size of the semiconductor device (SOP 7).

Furthermore, in the frame structure in which the support pins and the die pads are formed as different parts, the lead frame is formed of two types of materials. Therefore, the cost is high and a processing cost of coupling the support pins and the die pads to each other is also required, and thus the cost of the semiconductor device further increases.

Moreover, also in ensuring the coupling accuracy at the time of coupling the support pins and the die pads to each other, the size of the die pads needs to be much larger than the chip size, and thus the above frame structure cannot be applied to a small semiconductor device.

Next, modifications of the present embodiment will be described.

FIG. 11 is a partial plan view showing a first modification of the separation method of the second support pins (before injecting a resin) in the assembling of the semiconductor device shown in FIG. 1. FIG. 12 is an enlarged partial plan view showing a structure of a D portion in FIG.

11. FIG. 13 is a partial plan view showing the first modification of the separation method of the second support pins (after injecting a resin) in the assembling of the semiconductor device shown in FIG. 1. FIG. 14 is an enlarged partial plan view showing a structure of a G portion in FIG. 13. FIG. 15 is an enlarged partial plan view showing a detailed structure of FIG. 14.

The first modification shown in FIGS. 11 to 15 shows a modification of the separation method of the second support pins 3 e and 3 j arranged between the inner leads 3 b adjacent to each other, the first modification is different from the method of cutting off the support pins together with the tie bars 3 g in the tie bar cut process after the resin sealing as shown in FIG. 10, and the first modification is a method of separating the support pins by tearing off the support pins by an injecting pressure of a resin in the resin sealing process. That is, in the resin sealing process, the inside of the tie bars 3 g is filled with the sealing resin 8 shown in FIG. 13, and thus the pressure of the sealing resin 8, acting on the tie bars 3 g is used. The tie bars 3 g are pressed and deformed by the pressure of the sealing resin 8 when the resin is injected, and the second support pins 3 e and 3 j connected to the tie bars 3 g are torn off by the deformation of the tie bars 3 g.

Specifically, first, as shown in FIGS. 11 and 12, before the sealing resin 8 of FIG. 13 is injected into the resin molding die 9 in FIG. 6, block members 11 are arranged outside the tie bars 3 g with a clearance 12 of a distance E from the tie bar 3 g being provided between them. At this time, as shown in FIG. 12, when an allowable amount of deformation of the tie bar 3 g deformed by the pressure of the sealing resin 8 is defined as E, the amount of deformation of the tie bar 3 g can be set by the distance E of the clearance 12 between the block member 11 and the tie bar 3 g.

In addition, by the distance E being set to be equal to or greater than a distance F between a torn-off portion 3 r in FIG. 11 of the second support pins 3 e and 3 j and the outer periphery of the sealing body 4 in FIG. 12 (the contour of the mold) formed by the resin sealing (E>=F), the support pins can be torn off inside the outer periphery of the sealing body 4.

Furthermore, since the maximum amount of deformation of the tie bar 3 g is the distance E, it is possible to prevent the deformation of the tie bar 3 g from being greater than necessary.

Note that, as shown in an H portion in FIG. 12, the tie bar 3 g to which no support pin is connected need not be deformed, and thus the block member 11 is arranged at a position slightly in contact with the tie bar 3 g without providing a clearance from the tie bar 3 g.

Furthermore, as shown in portions I in FIG. 12, it is preferable that there is formed a groove portion 3 p (for example, V-groove), a step portion, or a notch in the torn-off portion 3 r shown in FIG. 11 near the tip of the second support pins 3 e and 3 j so that the cross-section area of the torn-off portion 3 r is reduced. By the groove portion 3 p, the step portion, or the notch being formed in the torn off portion 3 r near the tip of the second support pins 3 e and 3 j, the support pins can be easily torn off and the stress applied to the support pins 3 e and 3 j can be reduced, when the second support pins 3 e and 3 j are torn off.

It is preferable that the torn-off portions 3 r of the second support pins 3 e and 3 j are formed at positions inside the outer periphery of the sealing body 4 to be formed. Thereby, it is possible to seal the second support pins 3 e and 3 j including the tips thereof inside the sealing body 4.

Furthermore, the timing when the deformation of the tie bars 3 g and the fracture (tearing off) of the second support pins 3 e and 3 j occur is, as shown in FIGS. 13 and 14, the final stage of the resin sealing process after the sealing resin 8 is injected via a gate 9 d of the resin molding die 9 (see FIG. 6) and a resin flow 8 a fills the inside of the resin molding die 9, that is, the timing when the filling of the sealing resin 8 is substantially completed and a set final pressure is applied. At this time, the sealing resin 8 is a fluid that has not yet cured, a pressure P of the sealing resin 8 is applied to the tie bars 3 g as shown in FIG. 14, the tie bars 3 g are deformed by the pressure P as shown in areas around portions I in FIG. 14, and the second support pins 3 e and 3 j are torn off at the torn-off portions 3 r thereof by the deforming force of the tie bars 3 g, as shown in portions I in FIG. 15.

Note that the second support pins 3 e and 3 j are fractured and the sealing resin 8 flows into a gap between the fractured support pins, but the amount of the sealing resin 8 that flows into the gap is extremely small compared with the volume of the sealing body 4, and thus the die pads 3 a and 3 h do not vibrate (shift) vertically and are not deformed even though the holding forces of the die pads 3 a and 3 h are lost due to the fracture of the support pins.

After the second support pins 3 e and 3 j are torn off, the tips of the second support pins 3 e and 3 j are covered by the sealing resin 8. That is, the gaps between the second support pins 3 e and 3 j fractured inside and the outer periphery of the sealing body 4 (the gaps between the torn-off pins shown in the portions I in FIG. 15) are filled with the sealing resin 8, and thus the torn-off tips of the second support pins 3 e and 3 j are brought into a state of being buried in the sealing body 4.

After completion of the sealing, the second support pins 3 e and 3 j that are torn off at the torn-off portions 3 r are buried in the sealing body 4 and cannot be seen from outside, and thus the appearance of the SOP 7 is not damaged.

In addition, it is possible to prevent the degradation of the humidity resistance due to penetration of liquid from the outside of the sealing body 4, prevent the degradation of the insulation resistance, and prevent the generation of the migration between a support pin and a lead adjacent to the support pin, and thus the reliability of the SOP 7 can be enhanced.

Furthermore, after the second support pins 3 e and 3 j are torn off by the deformations of the tie bars 3 g, the deformations of the tie bars 3 g hit the block members 11 and stop, and thus the tie bars 3 g are not deformed any more, so that it is possible to prevent the respective inner leads 3 b connected to the tie bars 3 g from being deformed.

Note that, as shown in J portions in FIG. 12, the groove portion 3 p such as a V-groove, a step portion or the like are formed at positions located inside the outer periphery of the sealing body 4 of the respective inner leads 3 b, and thus it is possible to prevent the degradation of the humidity resistance, the degradation of the insulation resistance and the like due to penetration of liquid from the outside, and to enhance the reliability of the SOP 7.

Next, the second to the fourth modifications will be described.

FIG. 16 is an enlarged partial plan view showing a structure of a lead frame of the second modification used in the assembling of the semiconductor device of the embodiment. FIG. 17 is a partial plan view showing stability of die pads of the lead frame shown in FIG. 16, and FIG. 18 is an enlarged partial plan view showing a structure of a lead frame of the third modification used in the assembling of the semiconductor device of the embodiment. Moreover, FIG. 19 is a partial plan view showing stability of die pads of the lead frame shown in FIG. 18, FIG. 20 is an enlarged partial plan view showing a structure of a lead frame of the fourth modification used in the assembling of the semiconductor device of the embodiment, and FIG. 21 is a partial plan view showing stability of die pads of the lead frame shown in FIG. 20.

In the second modification shown in FIGS. 16 and 17, in the lead frame 3 in which two die pads 3 a and 3 h are provided side by side, two second support pins 3 e and 3 j connected to each of the two die pads 3 a and 3 h are arranged adjacent to each other as shown in an A portion in FIG. 16 and both die pads 3 a and 3 h are pads each having a three-point support configuration of being supported at three points by three support pins.

Furthermore, the second support pins 3 e and 3 j of each of the three support pins are connected to a tie bar 3 g.

Also in the lead frame 3 of the second modification shown in FIGS. 16 and 17, as shown in FIG. 17, the triangular shapes of both the triangle A of the die pad 3 a and the triangle B of the die pad 3 h are well-balanced, and thus it can be found that the die pads 3 a and 3 h are in a support state of a high degree of stability.

In addition, in the third modification shown in FIGS. 18 and 19, in the lead frame 3 in which two die pads 3 a and 3 h are provided side by side, two second support pins 3 e and 3 j connected to each of the two die pads 3 a and 3 h are arranged between inner leads 3 b adjacent to each other as shown in portions A in FIG. 18 and each of the second support pins 3 e and 3 j is connected to a tie bar 3 g.

Therefore, both die pads 3 a and 3 h have three-point support configurations of being supported by three support pins.

Also in the lead frame 3 of the third modification shown in FIGS. 18 and 19, as shown in FIG. 19, the triangular shapes of both the triangle A of the die pad 3 a and the triangle B of the die pad 3 h are well-balanced, and thus it can be found that the die pads 3 a and 3 h are in a support state of a high degree of stability.

In addition, in the fourth modification shown in FIGS. 20 and 21, in the lead frame 3 in which two die pads 3 a and 3 h are provided side by side, each of two second support pins 3 e and 3 j connected to the two die pads 3 a and 3 h, respectively, is arranged between inner leads 3 b and connected to a tie bar 3 g, as shown in portions A in FIG. 20. Furthermore, one die pad 3 a is also supported by a fourth support pin 3 m shown in a B portion in FIG. 20, which is connected to a tie bar 3 g.

That is, the die pad 3 a has a four-point support configuration of being supported by four support pins and the die pad 3 h has a three-point support configuration of being supported by three support pins.

The lead frame 3 of the fourth modification shown in FIGS. 20 and 21 also includes the die pad 3 a having a four-point support configuration and the die pad 3 h having a three-point support configuration, and as shown in FIG. 21, the quadrangular and triangular shapes of the quadrangle A of the die pad 3 a and the triangle B of the die pad 3 h, respectively, are well-balanced, and thus it can be found that the die pads 3 a and 3 h are in a support state of a high degree of stability.

Also in the SOP 7 assembled by using the lead frame 3 of the second to the fourth modifications described above, it is possible to obtain the same effects as those obtained by the SOP 7 shown in FIGS. 1 to 3 and by the assembling of the SOP 7.

Next, the fifth to the seventh modifications will be described.

FIG. 22 is an enlarged partial plan view and partial cross-sectional views showing a structure of a lead frame of the fifth modification used in the assembling of the semiconductor device of the embodiment. FIG. 23 is an enlarged partial plan view showing a structure of a lead frame of the sixth modification used in the assembling of the semiconductor device of the embodiment. FIG. 24 is a cross-sectional view showing a structure taken along A-A line in FIG. 23. In addition, FIG. 25 is an enlarged partial plan view and partial cross-sectional views showing a structure of a lead frame of the seventh modification used in the assembling of the semiconductor device of the embodiment.

The fifth modification shown in FIG. 22 is a lead frame 3 having a shape in which two die pads 3 a and 3 h are provided side by side and each of two second support pins 3 e and 3 j connected to the two die pads 3 a and 3 h respectively is arranged between inner leads 3 b and is connected to a tie bar 3 g in the same manner as the die pads 3 a and 3 h of the lead frame 3 shown in FIG. 8.

Furthermore, in one die pad 3 a, bent portions 3 n are formed in some of the support pins (here, the first support pin 3 d and the third support pin 3 f) that support the die pad 3 a and in an edge portion of the die pad 3 a.

That is, as shown in an A portion and a B portion in FIG. 22, the bent portion 3 n is formed in the first support pin 3 d and the third support pin 3 f along the extending direction of the support pins, and another bent portion 3 n connected to the above bent portions 3 n is formed in a part of edge portion (end portion) of the die pad 3 a. Note that the bent portions 3 n may be formed so that the cross-section of the support pins has an inverted V-shape as shown in the A portion and the B portion or may be formed so that the cross-section has a V-shape.

By the formation of the bent portions 3 n in the edge portion (end portion) of the die pad 3 a and the support pins, it is possible to reduce the vertical movement (vibration) of the die pad 3 a in the die bonding process, the wire bonding process, and the like.

Moreover, the shapes of contact surfaces of the lower molding die 9 a and the upper molding die 9 b of the resin molding die 9 shown in FIG. 6 when the resin sealing is performed are caused to correspond to the shapes of the bent portions 3 n of the support pins, and thus it is possible to reduce the vertical movement (vibration) of the die pad when the resin is injected in the resin sealing process. As a result, the reliability of the semiconductor device can be enhanced.

Note that the bent portions 3 n in the edge portion (end portion) of the die pad and in the support pins may be formed in any one of the die pads or any one of the support pins, or may be formed in the die pads or the support pins.

Next, in the same manner as the die pads 3 a and 3 h of the lead frame 3 shown in FIG. 8, the sixth modification shown in FIGS. 23 and 24 is a lead frame 3 having a shape in which two die pads 3 a and 3 h are provided side by side and each of two second support pins 3 e and 3 j connected to the two die pads 3 a and 3 h respectively is arranged between inner leads 3 b and is connected to a tie bar 3 g.

In the lead frame 3 of the sixth modification, as shown in a Q portion and an R portion in FIG. 23, a folded portion 3 ag is formed in at least one edge portion (end portion) corresponding to one of four sides of each of the die pads 3 a and 3 h. Here, as shown in FIG. 24, the folded portions 3 ag are formed to be folded toward the lower surfaces 3 ab and 3 hb.

In this way, by the formation of the folded portions 3 ag so as to be folded toward the lower surfaces 3 ab and 3 hb, the mounting of the semiconductor chips 1 and 2 cannot be prevented.

Note that the folded portion 3 ag may be formed corresponding to at least any side of one die pad of the die pads.

As described above, by the formation of the folded portions Sag in the die pad 3 a and the die pad 3 h, it is possible to enhance the rigidity of the die pads 3 a and 3 h themselves. As a result, it is possible to reduce the vertical movement (vibration) of each of the die pads 3 a and 3 h in the die bonding process, the wire bonding process, and further, the resin sealing process. Accordingly, the reliability of the semiconductor device can be enhanced.

Furthermore, in the same manner as the die pads 3 a and 3 h of the lead frame 3 shown in FIG. 8, the seventh modification shown in FIG. 25 is a lead frame 3 having a shape in which two die pads 3 a and 3 h are provided side by side and each of two second support pins 3 e and 3 j connected to the two die pads 3 a and 3 h respectively is arranged between inner leads 3 b and is connected to a tie bar 3 g.

Moreover, the shape of the lead frame 3 in FIG. 25 is a combined shape of the bent portions 3 n (A portion and B portion) in the support pins and the edge portion (end portion) of the die pad in FIG. 22, and the folded portions 3 ag (Q portion and R portion) in another edge portion (another end portion) of the die pads in FIG. 23.

Thereby, the rigidity of the die pads themselves can be enhanced, and at the same time, the rigidity of the support pins can also be enhanced.

As a result, it is possible to reduce the vertical movement (vibration) of the die pad 3 a in the die bonding process, the wire bonding process, and the like. Furthermore, the shapes of the contact surfaces of the lower molding die 9 a and the upper molding die 9 b of the resin molding die 9 shown in FIG. 6 when the resin sealing is performed are caused to correspond to the shapes of the bent portions 3 n of the support pins, and thus it is possible to reduce the vertical movement (vibration) of the die pad when the resin is injected in the resin sealing process.

As a result, it is possible to enhance the reliability of the semiconductor device.

Note that the folded portion 3 ag and the bent portion 3 n in the edge portion (end portion) of the die pad and the bent portion 3 n in the support pin may be formed in any one of the die pads or any one of the support pins, or may be formed in the die pads or the support pins.

Although the invention made by the inventors has been specifically described on the basis of the embodiment, it is needless to say that the present invention is not limited to the foregoing embodiment, and can be variously modified within the scope not departing from the gist of the invention.

For example, in the embodiment described above, while the SOP is taken up and described as an example of the semiconductor device, the semiconductor device may be other semiconductor devices if the semiconductor devices include the die pads and the support pins that support the die pads. That is, the semiconductor device may be a discrete device other than SOP, and further, may be a semiconductor device such as QFN (Quad Flat Non-leaded Package) or QFP (Quad Flat Package). 

What is claimed is:
 1. A semiconductor device comprising: a die pad, which includes an upper surface and a lower surface opposite to the upper surface, the upper surface forming a rectangular shape in plan view; a plurality of support pins that support the die pad; a plurality of inner leads arranged around the die pad; a plurality of outer leads connected to each of the inner leads; a semiconductor chip which includes a main surface and a back surface opposite to the main surface and in which a plurality of electrode pads is formed in the main surface, the semiconductor chip being mounted over the die pad so that the back surface faces the upper surface of the die pad; a plurality of wires which electrically couple the electrode pads of the semiconductor chip to the inner leads respectively; and a sealing body that seals the support pins, the inner leads, the semiconductor chip, and the wires, wherein a first support pin of the plurality of support pins is integrally formed together with the die pad, wherein the first support pin is terminated inside the sealing body.
 2. The semiconductor device according to claim 1, wherein a tip of the first support pin is buried inside the sealing body.
 3. The semiconductor device according to claim 1, wherein the support pins include a first support pin arranged between any two of the inner leads.
 4. The semiconductor device according to claim 1, Wherein the support pins include a second support pin connected to the outer lead.
 5. The semiconductor device according to claim 4, Wherein the support pins include a third support pin connected to a side of the die pad different from sides to which the first support pin and the second support pin are connected.
 6. The semiconductor device according to claim 1, wherein a folded portion is formed in an edge portion of the die pad.
 7. The semiconductor device according to claim 5, wherein a bent portion is formed in at least any of the first, the second, and the third support pins. 